Mesosphere and Lower Thermosphere Dynamics Studies Employing the Southern Argentina Agile MEteor Radar (SAAMER), Correlative Measurements, and Modeling

利用阿根廷南部敏捷流星雷达 (SAAMER) 进行中层和低层热层动力学研究、相关测量和建模

• 批准号: 2131350
• 负责人: David Fritts
• 金额: $ 76.8万
• 依托单位: GLOBAL ATMOSPHERIC TECHNOLOGIES AND SCIENCES, INC.
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2131350&HistoricalAwards=false
• 关键词: Mesosphere; Lower; Thermosphere; Dynamics; Studies

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2). This award supports the continued operations of a suite of instruments including the SAAMER meteor radar at the southern tip of South America known as Terra del Fuego. The award will support the continued study of large- and small-scale dynamics that play many roles in the mesosphere and lower thermosphere (MLT). Tides and planetary waves (PWs) account for the major variability on larger horizontal and vertical scales because they propagate largely without strong attenuation from sources in the troposphere and stratosphere into the MLT and above. These have been studied using MLT radar, lidar, and satellite measurements for many years, and they account for the major large-scale variability of the MLT. Smaller-scale gravity waves (GWs) arise from multiple sources modulated by tropospheric weather, especially mountain waves (MWs), convective GWs, inertia-GWs, and secondary GW (SGW) generation where GWs from other sources attain large amplitudes. Most of these dynamics have been studied extensively, both observationally and via modeling, but the smaller scales, and their large range of dynamics, interactions, and instabilities have prevented a quantitative understanding of their dynamics and influences to date. The importance of these large- and small-scale dynamics derives from their major influences in the MLT and extending to lower and higher altitudes. Observations and analyses of large- and small-scale dynamics play central roles in identifying and understanding the diverse processes that determine the structure and variability of the atmosphere. Such efforts are especially needed in the MLT, where the dynamics are driven by energy and momentum fluxes due to GW propagation from sources at lower altitudes that vary strongly with tropospheric weather. MLT responses are often strongly nonlinear due to large GW amplitude increases leading to instabilities, turbulence, and forcing of mean and large-scale wave motions that are poorly understood at present. Analyses of observations by Aura MLS and MLT radars will quantify key PW and tidal dynamics. Observational guidance of GW responses at TdF and NAVGEM re-analyses would aid the detailed modeling addressing MW and more general GW dynamics, instabilities, forcing, and responses in the MLT. A Univ. of Colorado (CU) graduate student would receive training in state-of-the-art GW, KHI, and geophysical turbulence modeling and supercomputing. The collection, formatting, and provision of global MLT radar data for NAVGEM data assimilation would also be a significant benefit for the CEDAR community. The major larger-scale forcing and smaller-scale forcing and variability of the MLT is driven by GWs that account for the major vertical fluxes of horizontal momentum driving MLT dynamics where GW breaking and dissipation cause energy and momentum deposition. These lead to local flow accelerations, mixing, feedbacks on the larger-scale dynamics contributing to GW breaking, and induced residual circulations having impacts at lower altitudes. All these dynamics have been assessed to varying degrees in previous observational and/or modeling studies. The new award would study different processes that include the following: 1)effects of GW/tidal interactions on tidal amplitudes & phases and GWs at higher altitudes, 2) influences of intermittency in GW breaking, energy & momentum deposition, and mixing, 3) influences of large-scale Kelvin-Helmholtz instabilities (KHI) in GW & tidal shears, 4) sources and effects of GW “self-acceleration” dynamics, for which there is significant modeling & observational support, but the implications of which are largely unknown, and 5) influences on MLT structure and variability by transient PWs arising at lower altitudes. Initial conditions for these models would be provided by NAVGEM re-analyses extending to 140 km based on global MLT radar winds supporting the NAVGEM data assimilation efforts coordinated by GATS personnel.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该奖项是根据2021年《美国救援计划法》（公法117-2）全部或部分资助的。该奖项支持一套套件的持续运营，包括在南美南端的Saamer流星雷达，称为Terra del Fuego。该奖项将支持对大型和小规模动力学的持续研究，这些动力学在中层和较低的热层（MLT）中起着许多作用。潮汐和行星波（PWS）是较大的水平和垂直尺度的主要变异性，因为它们在很大程度上传播了对流层和草皮层中MLT及更高版本的强大衰减。多年来，它们已经使用MLT雷达，激光雷达和卫星测量进行了研究，它们解释了MLT的主要大规模差异。较小规模的重力波（GWS）是由对流层天气（尤其是山波（MWS），对流GWS，惯性GWS和次级GW（SGW）一代的多种来源引起的，其中其他来源的GWS来自其他来源的GWS。这些动力学大多数已经在观察和建模上进行了广泛的研究，但是较小的尺度以及它们众多的动态，相互作用和不稳定性却阻止了对迄今为止其动态和影响的定量理解。这些大型和小规模动力学的重要性源于它们在MLT中的主要影响，并延伸到较低和更高的高度。对大型和小型动态的观察和分析在识别和理解决定大气的结构和可变性的多样性过程中起着核心作用。在MLT中，尤其需要这种努力，在MLT中，由于GW在较低高度的源繁殖而导致的能量和动量通量驱动的动力学驱动，这些高度在对流层天气下差异很大。 MLT响应通常是由于GW放大器的大量增加而导致不稳定性，湍流和均值和大规模波动运动的强大响应，目前尚未理解。 AURA MLS和MLT雷达对观察的分析将量化关键PW和潮汐动力学。 TDF和Navgem重新分析的GW响应的观察性指导将有助于详细建模，以解决MW和更多一般的GW动态，不稳定性，强迫和MLT中的响应。一个大学。科罗拉多州（CU）的研究生将接受最先进的GW，KHI和地球物理湍流建模和超级计算的培训。全球MLT雷达数据的收集，格式和提供NAVGEM数据同化的数据也对Cedar社区也是一个重要好处。 MLT的主要大型强迫和较小的强迫和变异性是由GWS驱动的，GWS驱动了水平动量的主要垂直通量驱动MLT动力学，其中GW破裂和耗散会导致能量和动量沉积。这些导致局部流动加速度，混合，对有助于GW破裂的大型动力学的反馈，以及在较低高度的影响下诱发的残留循环。在先前的观察性和/或建模研究中，所有这些动力学都在不同程度上进行了评估。新奖项将研究包括以下内容的不同过程：1）GW/潮汐相互作用对较高高度的潮汐放大器和阶段和GW的影响，2）GW破裂，能量和动量沉积和混合的影响，3）大型Kelvin-Helmholtz Instabilitions（kelvin-Helmholtz inst in In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In In Insivelys（ GW“自我加速”动力学，为其具有重要的建模和观察支持，但其含义在很大程度上是未知的，以及5）对MLT结构和瞬态PW的影响。这些模型的初始条件将由Navgem Re-Analyses提供，该条件基于全球MLT雷达风扩展到140公里，支持由GATS人员协调的Navgem数据同化工作。该奖项反映了NSF的法定任务，并通过使用该基金会的知识分子优点和广泛的影响来评估NSF的法定任务。